Preparation and characterization of polysulfone/β-cyclodextrin polyurethane composite nanofiltration membranes

This work presents the preparation and characterization of polysulfone (PSf)/β-cyclodextrin (β-CD) polyurethane composite membranes using a modified phase inversion technique. β-CD polyurethane was blended with PSf at concentrations of 0–10% to prepare nanofiltration (NF) membranes for selective removal of Cd2+ ions from water at a working pH of 6.9. Mixed matrix β-CD polyurethane/PSf membranes were more hydrophilic with higher water permeability and higher Cd2+ rejection (up to 70%). However, the mixed matrix membranes were also rougher, less porous, took up more water, and were less mechanically stable. Further, FT-IR results indicate hydrogen bonding interactions between β-CD polyurethane and PSf, which suggests that the materials are compatible. Dead-end filtration tests suggest that mixed matrix membranes have higher water flux. This suggests that the combination of β-CD polyurethane with PSf can produce viable nanofiltration with improved flux without a compromise on its rejection ability.